The radiation image recording and reproducing method utilizes a radiation image storage panel containing a stimulable phosphor which absorbs a portion of a radiation energy (e.g., X-ray energy) when the radiation energy is applied to the stimulable phosphor and afterward produces a stimulated emission when a stimulating light or heat is applied to the radiation energy-absorbed phosphor.
Thus, the stimulable phosphor emits stimulated emission when excited with a stimulating light after having been exposed to a radiation as X-rays. Accordingly, the radiation having passed through an object or radiated by an object is absorbed by the phosphor layer of the storage panel in proportion to the applied radiation dose, and a radiation image of the object is produced in the storage panel in the from of a radiation energy-stored latent image. The radiation energy-stored image can be released as stimulated emission by sequentially irradiating the storage panel with a stimulating light. The stimulated emission is then photoelectrically detected to give electric signals, so as to reproduce a visible image from the electric signals.
Accordingly, the radiation image recording and reproducing method comprises the steps of causing the stimulable phosphor of the storage panel to absorb a radiation energy having passed through an object or having radiated from an object; sequentially exciting the stimulable phosphor with an electromagnetic wave such as visible light or infrared rays (stimulating light) to release the radiation energy stored in the phosphor as light emission (i.e., stimulated emission); photoelectrically detecting the emitted light to obtain electric signals; and reproducing the radiation image of the object as a visible image from the electric signals. The storage panel thus treated is subjected to a step for erasing a radiation image remaining therein, and then stored for the next recording and reproducing procedure. Thus, the radiation image storage panel can be repeatedly employed.
The radiation image storage panel employed in the above-describe method has a basic structure comprising a support and a stimulable phosphor layer provided on one surface of the support. If the phosphor layer is self-supporting, the support may be omitted. The phosphor layer usually comprises a binder and stimulable phosphor particles dispersed therein, but it may consist of agglomerated phosphor with no binder. The phosphor layer containing no binder can be formed by deposition process or firing process. Further, the layer comprising agglomerated phosphor soaked with a polymer is also known.
In general, a transparent film of polymer material is placed on a free surface (surface not facing the support) of the phosphor layer to keep the layer from chemical deterioration or physical damage. This surface protective film can be formed by various method, for example, by applying a solution of resin, by fixing a transparent resin film with adhesive, or by depositing inorganic materials on the phosphor layer.
The radiation image recording and reproducing method is very useful for obtaining a radiation image as a reproduced visible image, and it is desired for the radiation image storage panel employed in the method to have a high sensitivity and to give an image of high quality (such as high sharpness and high graininess).
Japanese Patent Provisional Publication 2001-124,898 discloses a radiation image storage panel having a stimulable phosphor layer and a light-reflecting layer provided thereon, wherein said light-reflecting layer scatters a stimulating light with a scattering length of 5 μm or less.